The invention relates to composites made of an elastic carrier medium consisting of polynorbornene (PNR) and magnetisable particles which are polarised reversibly in a magnetic field. Thus the mechanical properties, such as e.g. storage modulus G′ (describes the elastic behaviour or the energy storage) and loss modulus G″ (describes the viscous behaviour or the energy dissipation), of such elastomer composites can be increased rapidly and reversibly within wide limits (up to approx. two orders of magnitude) as a function of an external magnetic field. Wide-ranging application possibilities are produced herefrom, e.g. for adaptive damping systems, in which the damping force can be adjusted via the strength of the magnetic field.
Magnetically controllable elastomer composites, so-called magnetorheological elastomers (MRE), are already known in a general form. However magnetorheological fluids (MRF) in which the magnetisable particles are distributed in a carrier liquid are much more widespread. Because of the lack of chemical crosslinking, such materials do not however have a solid form but are liquid or irreversibly deformable as physically weakly crosslinked gels.
The possibility is likewise known to produce a chain-like orientation of the particles in an MRE during crosslinking by applying a magnetic field. Silicones have been used to date for this purpose and were used as pourable precursors. In addition, the use of other commercially widespread elastomers made of natural and synthetic rubber (e.g. nitrile rubber) are described in the literature; however only relatively small changes in the mechanical properties in the magnetic field were thus achieved. Also the use of different magnetisable particle materials in MRE was mentioned already in a general form.
The materials described in the state of the art can be found in the following literature sites: M. R. Jolly, J. D. Carlson, B. C. Munoz, T. A. Bullions, J. Int. Mat. Syst. Struct. 1996, 7, 613; J. M. Ginder, M. E. Nichols, L. D. Elie, J. L. Tardiff, SPIE 1999, Vol. 3675, 131; M. Lokander, B. Stenberg, Pol. Test. 2003, 245(22), 677.